Fold FULL worker state into BUSY.
1. Remove redundant total_workers_connected field which is same as size of worker
table.

2. total_worker_slots is deprecated in WQ stats and will reflect the number of
running tasks as default. total_workers_joined is similary deprecated and will
reflect size of worker table.

3. count of workers will reflect init + ready + active workers
Remove the worker states. Instead, use counts of known_workers which tracks all
workers that have identified themselves and available_workers that track workers
that with available resources. These are used in WQ stats, debugging, and places
where we need to know if workers are available for running a task.
Fix bug where we would try to dispatch a task immediately even if there are no
available workers. Thanks to Ben who noticed this.
Keep old log format that prints workers_full for backward compatability. And
mark workers_full as deprecated.
As a band-aid until #276, busy workers will reflect those running at least 1
task, while ready workers will represent its complement.
Merge branch 'master' of git://github.com/dpandiar/cctools into dpandiar-master

Remove worker states and some cleanup.

Remove worker states.
Clean up various worker-related counts.

Conflicts:
	work_queue/src/work_queue.c